What is it?

According to Opec, “crude oil is a naturally-occurring substance found in certain rock formations in the earth. It is a dark, sticky liquid which, scientifically speaking, is classified as a hydrocarbon. Crude oil is highly flammable and can be burned to create energy. Along with natural gas, derivatives from crude oil make an excellent fuel.”

Crude oil first came into large-scale commercial use in the US in the 19th century; since then, its derivatives such as petrol, kerosene and LPG have been widely used for many purposes. While it primarily serves as a fuel, refined crude oil products are also used for the production of petrochemicals, and as lubricants.

Opec says that world crude oil reserves are estimated at slightly more than 1.2 trillion barrels, of which its member countries hold approximately 78 percent.